There's nothing quite like an incumbent's predilection for corruption, bribery or sleazy sex for helping an underdog win a congressional seat. And there was plenty of muck to exploit in the 2006 midterm elections, when a raft of Republican scandals helped more than a dozen Democrats get elected in districts thought to be safely Republican.

But can they stay there? This year Republicans have pegged as top targets two "scandal babies" who defeated the most prominently shamed Republicans of 2006. Tim Mahoney, Representative from Florida's 16th Congressional District, holds the seat once occupied by Mark Foley, who resigned after revelations about his sexually explicit e-mails to House pages became public. Nick Lampson of Texas' 22nd District succeeded Tom DeLay, the Republican majority leader brought low by his connections to shady lobbyist Jack Abramoff.

Mahoney and Lampson "have been labeled kind of a pair of accidental Congressmen," says Isaac Wood of the University of Virginia's Center for Politics. Their districts are far from Democratic strongholds: Mahoney's went 54% for Bush in 2004, and voters in Lampson's patch cast 64% of their vote for Bush. "Both districts are very high on our priority list," says a spokesman for the National Republican Congressional Committee.

History suggests that scandal babies do not fare well when they face an opponent free of ethical baggage. Michael Patrick Flanagan, for example, won an improbable victory in the Republican tsunami of 1994 over scandal-scarred Democratic veteran Dan Rostenkowski, but he was crushed two years later by an energetic young Democrat named Rod Blagojevich (who went on to be elected governor of Illinois  and is now suffering through his own ethical travails). A scandal, it seems, is a onetime thing: it's helpful for getting elected but is of little use when re-election rolls around.

Lampson and Mahoney, however, aren't going down without a fight. Both highlight their relative independence from the Democratic leadership. A July press release from Mahoney touts his National Journal ranking as "the member of Congress who is in the absolute middle." Indeed, until 2005, Mahoney, a Palm Beach, Fla., businessman and banker, was a card-carrying Republican. His spokesman Charles Halloran insists that Mahoney's victory in 2006 was fueled more by disgust with Congress in general than by the Foley scandal in particular, and that in his campaign Mahoney tried to sidestep the messy affair. "In 2006 we were the only campaign in America that really couldn't run against Mark Foley," Halloran says. Mahoney's campaign has already raised an impressive $2.1 million for his re-election fight.

Lampson, perhaps stung by GOP charges of carpetbagging  he represented another Texas district in Washington for eight years  is presenting himself as a champion of causes near and dear to his suburban Houston constituents. Mike Malaise, a consultant to Lampson's campaign, says the Congressman "took moves in the House to block billions of dollar of cuts to NASA," one of the district's biggest employers. By running on local issues, Lampson hopes he can neutralize the Republicans' huge edge in voters' party preference. Malaise stresses Lampson's moderate credentials: "He has promised and has delivered to work across the aisle with Republicans." Lampson's campaign coffers already hold a respectable $1.3 million.

Still, Republicans are optimistic about their chances. In Texas they're running Pete Olson, a Navy veteran and former chief of staff to Republican Senator John Cornyn. Amy Goldstein, Olson's communications chief, talks up the candidate as a natural fit for the conservative district. "People are really upset" with Lampson, she says. "They don't feel that their values are being represented up in Washington." Florida Republicans have yet to pick their nominee, but observers say the favorite there is attorney Tom Rooney, an Army veteran and nephew of Pittsburgh Steelers president Dan Rooney.

Both districts are so pro-Republican that even the Bush Administration  political poison almost everywhere else  is seen as a plus. Vice President Dick Cheney, hardly a vote getter in most Republican districts, has already made a fund-raising appearance on Olson's behalf, and Florida Republicans are expected to make use of popular former Governor Jeb Bush. Both Lampson and Mahoney are members of the Blue Dog caucus of conservative Democrats, and Mahoney has so far pointedly refused to endorse Barack Obama. Yet Republicans are quick to link the two with another bête noire for Republicans, House Speaker Nancy Pelosi. What's clear, however, is that as Congress' biggest scandal babies, Mahoney and Lampson will have to win this one on their own.